Thermal plasmas and lasers have been widely used in medicine to cut tissues through heating. The effects of such thermal plasmas on tissues are non-selective and difficult to control because they occur primarily through transfer of intense heat. In contrast, non-thermal plasma does not produce heat, thus its effects are more selective. Although electrical discharges that generate non-thermal plasma have been known for a long time, their clinical potential has been largely ignored and until recently, applications have been confined to sterilization of inert surfaces or modulation of cell attachment. The exploitation of cold plasma for clinical applications requires the mechanistic understanding of the interaction of non-thermal plasma with living tissues.
US patent application 2010/0130911 describes a plasma source device which provides a reduced pressure in the ionization chamber. This device is adapted for the sterilization of wounds. Patent application WO2005/084569 discloses a disposable gas plasma tissue resurfacing instrument for skin treatment comprising an electromagnetically resonant focusing element. The aforementioned patent applications pertain to treating the tissues on the surface of wounds.
It has been shown that non-thermal plasma created by dielectric barrier discharge (DBD) has dose-dependent effects on mammalian cells in culture that range from increasing cell proliferation to inducing apoptosis. It has been further shown that these effects are primarily due to the formation of intracellular reactive oxygen species (ROS), which are known to cause DNA damage (S. Kalghatgi, C. Kelly, E. Cerchar, A. Fridman, G. Friedman, J. Azizkhan-Clifford, Effects of Non-Thermal Plasma on Mammalian Cells PLoS ONE, 21 Jan. 2011. 6(1)). US patent application 2010/0145253 relates to application of non thermal plasma to living tissue in vitro. Thus means and methods for inducing a regenerative effect on a whole subject, in vivo, using non thermal gas plasma treatment are still required.
The influence of plasma treatment on seed germination has recently been studied (I. Filatova et al. The effect of plasma treatment of seeds of some grain and legumes, on their sowing quality and productivity, Rom. Journ. Phys. Vol. 56, 139-143, 2011; S. Bozena et al, Influence of plasma treatment on wheat and oat germination, IEEE Transactions on plasma science, vol. 38, 2010). These studies describe an apparatus comprising a vacuum chamber, a rotary pump and a microwave resonator. The exposure time to the plasma treatment was for a period of several minutes to more than 40 min. Furthermore, the effects reported by these studies mainly relate to the seed coat surface and seed coat sterilization.
There is therefore a long felt and unmet need to provide systems and methods for inducing a regenerative effect on a subject, using efficacious non thermal gas plasma treatments and protocols which can be applied conveniently.